https://www.bleepingcomputer.com/news/security/hackers-hijack-telegram-email-accounts-in-ss7-mobile-attack/

Hackers with access to the Signaling System 7 (SS7) used for connecting mobile networks across the world were able to gain access to Telegram messenger and email data of high-profile individuals in the cryptocurrency business.

In what is believed to be a targeted attack, the hackers were after two-factor authentication (2FA) login codes delivered over the short messaging system of the victim’s mobile phone provider.